A moulded plastics coupling body and a tube coupling comprising such a body

Abstract: The disclosure relates to a seal arrangement in a resilient moulded plastics body (10) having a bore (11) open at one end (12) to receive a cylindrical component. The seal is formed by a plurality of resiliently flexible annular lips (22) moulded integrally with the bore at spaced locations along the bore and extending inwardly of the bore to seal with the surface of a cylindrical component (e.g. a tube) inserted in the bore. The lips are angled to extend both inwardly and axially along the bore towards said open end to receive the cylindrical component. Preferably three sealing lips are provided.

Description: This invention relates to moulded plastics coupling bodies for tube couplings. GB-A-1520742, 1573757 and 2132295 disclose tube couplings in which a coupling body has throughway open at one end to receive a tube with an internal tapered cam surface converging towards the open end of the body in which a collet is disposed with resilient arms which engage the taper cam surface to be forced inwardly thereby to grip and hold the tube in the body. The throughway in the body is formed with a step facing towards the open end and an O-ring seal is located in the throughway adjacent the step to form a seal between the outer surface of the tube and the inner surface of the coupling body to prevent loss of fluid therefrom. GB-A-2172356 discloses a further form of tube coupling body generally in accordance with the above arrangement and provided with an inner liner extending lengthwise of the body with integral annular seals for sealing with a tube extending into the body. EP-A-0518679 which forms the basis for the preamble to claim 1 as set out hereinafter discloses a further form of tube coupling body in which the body is moulded in an elastomeric material and a throughway in the body has integral V-section sealing rings moulded around the inner surface of the throughway for sealing engagement with a tube inserted into the coupling body. This invention provides moulded plastics coupling body for a tube-coupling having a throughway open at one end to receive a tube and a plurality of resiliently flexible annular lips moulded integrally with the coupling body at spaced locations along the throughway to seal with a surface of a tube inserted into the throughway, wherein the lips are angled to extend both inwardly and along the throughway towards the open end thereof to receive the tube. Preferably three or more lips are provided as appropriate according to the length of bore available. In one application, the coupling body is adapted to fit in a further component. In the latter case the body may have encircling sealing means for sealing with the further component into which it is to be fitted. In a further arrangement according to the invention the body may be formed with an integral openable diaphragm for closing the bore in the body. By way of example the diaphragm may be formed with a multiplicity of radially extending slits to create a number of fingers formed integrally with the bore of the body which can be deflected to open the bore in the body. In a still further arrangement the body may have a flap valve for closing the bore in the body. More specifically the flap valve may have a rupturable connection to the body on the other side thereof to open when the cylindrical component is inserted in the body. In yet a further arrangement a separate valve disc may be mounted in the bore in the body trapped between adjacent sealing lips to be released when subjected to an excess load or pressure. The invention also provides a tube coupling comprising a moulded plastics body according to any of the above arrangements, the throughway having an open end in which a tube locking device is located to receive and lock a tube in the body and said plurality of encircling lips being formed adjacent said open end to receive and seal with the tube located in the coupling body. The following is a description of some specific embodiments of the invention, reference being made to the accompanying drawings, in which: Figure 1 is a cross-sectional view through a tube coupling body incorporating a seal arrangement in accordance with the invention; Figure 2 is a cross-sectional view through a separate body having a throughway and seal arrangement in accordance with the invention; Figure 3 is a similar view to Figure 2 showing an alternative form of body; Figure 4 is a similar view to Figure 3 incorporating an openable diaphragm; Figure 5 is an end view of the arrangement shown in Figure 4; Figure 6 is a similar view to Figure 4 with a tube inserted through the body to open the diaphragm; Figure 7 is a similar view to Figure 3 with the addition of a flap valve shown in the closed position; Figure 8 is a similar view to Figure 7 with the flap valve shown open; Figure 9 is a similar view to Figure 3 showing a closure disc in place in the bore of the body; Figure 10 shows the disc displaced by insertion of a tube in the body; Figure 11 shows a modification of the body of Figure 2 applied to a non-return valve; Figure 12 is an end view of the non-return valve of Figure 11; Figure 13 is a similar view to Figure 11 showing an alternative valve design; and Figure 14 is an end view of the arrangement of the valve of Figure 13. Referring firstly to Figure 1 of the drawings, there is shown a tube coupling of the type generally described and illustrated in GB-A-1,520,742, 1,573,757 and 2,132,295. The coupling comprises a coupling body 10 which is moulded in any suitable resilient/flexible plastics material including nylon, polyethylene, polypropylene or an elastomeric polyester material such as that sold under the Trade name "Hytrel". The coupling body has a throughway 11 which leads through a number of enlarged sections to a reduced diameter opening 12 at one end of the body. The throughway 11 is increased in diameter by a step 13 to form a first enlarged diameter section 14 to receive an end part of a tube (not shown) to be located in the coupling body. Section 14 gives way at a rounded step 15 to an enlarged diameter sealing section 16 which in turn gives way at a step 17 to an enlarged section 18 in which a collet 19 is engaged for locking a tube in the tube coupling. The collet has resilient fingers 20 engageable with a tapered cam surface 21 reducing in diameter towards the open end 12 of the coupling body to cause the heads of the collet to grip and engage a tube passing through the collet to lock the tube in the coupling body. The enlarged sealing section 16 of the throughway is formed with three (or more) spaced inclined integral annular sealing lips or fins 22 which are angled towards the open end of the body. The lips seal with the outer surface of the tube when the tube is pressed into the coupling body. The coupling body is formed as an injection moulding and the lips are formed by deep grooves in a core pin in the mould. Because they are angled, they can be bumped or stretched off the core. Their shape and design allows them to seal on the tube in both directions. As a tube is inserted into the coupling body, the lips bend in with the tube giving a tight and effective seal. Figure 2 shows the application of the seal arrangement to a separate sleeve 25 which is adapted to be inserted in a further component. The sleeve 25 has integral external sealing rings or lips 26 extending radially of the outer surface of the sleeve to seal with the bore in which the sleeve is to be located. The sleeve may also be provided with an end seal to engage with the body in which it is mounted. Figure 3 shows a variant of the arrangement shown in Figure 2 in which the radial lips 26 are replaced by two rounded contours 27 on the external periphery of the sleeve. Figures 4 to 6 show a similar arrangement to that of Figure 3 with the addition of an openable diaphragm 28 at one end of the sleeve. The diaphragm is formed integrally with the coupling body and has a plurality of closely spaced radial slots to create a number of separate diaphragm fingers 29 which can open in response to a pressure differential or can be opened by insertion of a tube through the sleeve as shown in Figure 6. Figures 7 and 8 show a further variant of the sleeve design of Figure 3 provided with an integral flap valve 30 hinged at its periphery to one side of the sleeve 25 and with a frangible or weak connection 31 on the opposite side. Thus insertion of a tube through the sleeve bursts open the flap valve as shown in Figure 8. Figures 9 and 10 show a similar arrangement except that the flap valve is formed by a separate disc 33 lodged initially between adjacent sealing lips and which can be displaced by insertion of a tube through the sleeve. It will be appreciated that the seal arrangements described above can be incorporated in a variety of other devices. By way of example Figures 11 to 14 show applications of the sleeve 25 of Figure 2 to a common types of non-return valve arrangements.

Claims: A moulded plastics coupling body (10) for a tube-coupling have a throughway (11, 16) open at one end (12) to receive a tube and a plurality of resiliently flexible annular lips (22) moulded integrally with the coupling body at spaced locations along the throughway (16) to seal with a surface of a tube inserted into the throughway, characterised in that the lips (22) are angled to extend both inwardly and along the throughway towards the open end (12) thereof to receive the tube. A coupling body as claimed in Claim 1, characterised in that three or more lips (22) are provided. A coupling body as claimed in Claims 1 or claim 2, characterised in that the coupling body (10) is adapted to fit in a further component. A coupling body as claimed in Claim 3, characterised in that the coupling body (10) has encircling sealing means (26) for sealing with the further component into which it is to be fitted. A coupling body as claimed in any of Claims 1 to 4, characterised in that the coupling body (10) is formed with an integral openable diaphragm (28) for closing the throughway in the body. A coupling body as claimed in Claim 5, characterised in that the diaphragm (28) is formed with a multiplicity of radially extending slits to create a number of fingers (29) formed integrally with the throughway of the body which can be deflected to open the throughway in the body. A coupling body as claimed in any of Claims 1 to 4, characterised in that the body has a flap valve (30) for closing the throughway in the body. A coupling body as claimed in Claim 7, characterised in that the flap valve (30) is hinged to the body on one side thereof and has a ruptural connection to the body on the other side thereof to open when subjected to an excess pressure or load. A coupling body as claimed in any of Claims 1 to 5, characterised in that a separate valve disc is mounted in the throughway in the body trapped between adjacent sealing lips to be released when subjected to an excess load or pressure. A coupling body as claimed in any of Claims 1 to 9, characterised in that the plastics body has an extended reduced diameter neck section at the opposite end of the throughway to said open end. A coupling body as claimed in Claim 10, characterised in that the neck section has an oval or flattened cross-section. A tube coupling comprising a coupling body as claimed in any of the preceding claims and a tube locking device (19,20) located in the open end of the throughway to receive and lock a tube in the body, and said plurality of encircling lips being formed adjacent said open end to receive and seal with a tube located in the coupling body.

Inventors: GUEST JOHN DEREK, GUEST, JOHN DEREK
Applicants: GUEST JOHN D, GUEST, JOHN DEREK
Application year: 1994
Main classification: F16J15
IPC codes: F16J15, F16L17, F16L37